Gear ratios of vehicles are generally fixed to limited numbers of gears. These gears try to establish an ideal relationship between the input force of the motor and the speed of motion of the vehicle. Thus, at lower speeds, higher torque is applied to the driving axle while maximum speed is low; and at higher speed less torque is required but maximum speed is high. Maximum engine torque is usually constant while driving torque requirements vary greatly with speed and road topology. Ideally, a continuous gear shifting would optimize driving conditions. Today's standard automobile transmissions generally provide 3 to 5 gear ratios and are manufactured with many parts. Road topology, frequent shifting of gears and many parts all tend to create high maintenance and non-optimal driving performance.
U.S. Pat. No. 3,747,424 describes a speed reducing gear having a frustoconical body acting as the reducing mechanism driving a horizontal output shaft. A horizontally engaged input drive shaft (worm gear) can be moved along the gradiated surface of the frustoconical body to reduce the speed ratio between the input and output. The invention requires a 90 degree angle between the input and output shafts making it awkward for a transmission shaft. It also requires a worm type interface for force transfer because the contact area of input to output would be very slight without a worm interface. It is also designed as a speed reducer.
U.S. Pat. No. 5,525,119 discloses a mechanism for varying rotational speed between two rotary shafts. It employs an intermediate roller contacting two cones. Speed variation is employed by the position of the roller between the two oppositely mounted cones while the roller is under pressure against the surfaces of both cones.
U.S. Pat. No. 4,161,890 discloses an improvement to the contact surfaces in preventing slippage between two substantially inelastic members that are in frictional engagement.
U.S. Pat. No. 4,183,253 discloses a moveable power transfer wheel interconnecting a pair of dual cones. Movement of the transfer wheel between both sets of cones varies input/output speed ratio.
What is needed is a mechanism employing direct drive means while able to vary the input/output speed ratio with no intermediate contacting parts. What is also needed is a mechanism to have the transfer of power directly between an input and an output member. What is further needed is a geared lowest gear for low speed torque.
The present invention resolves these problems. The present invention provides an ability to vary speed directly between two members while providing direct power transfer with no intermediate parts. The present invention also provides in-line drive. That is, the input shaft and output shaft can be maintained with their individual axis in a coplanar relationship. The present invention is also simple to manufacture with minimal parts. The present invention is also easily adjustable and maintainable. The present invention also provides a geared lower gear for positive slip free power transfer in low gear.